Concentration of sulphur



i Patented Jam-1, 1929.

Artur orrics.

I EDWARD HOIT NUTTER, OF SAN FRANCISCO, AND JOHN LITTLE FORD', F ALAMEDA, CALIFORNIA, ASSIG-NORS TO MINERALS SEPARATION NORTH AMERICAN CORPORA- TION, OF NEW YORK, N. Y., A CORPORATION OF MARYLAND.

CONCENTRATION OF SULPHUR.

No Drawing.

This invention relates to the concentration of sulphur, from its ores, and is herein disclosed as applied to the obtaining of a highly purified sulphur from' ores found in Wyoming.

Sulphur containing much more than 2% of gangue fails to meet the requirements of the commercial markets. It has been hitherto found possible to concentrate the sulphur in these and other ores to obtain a concentrate containing upwards of 7 of sulphur, but the products hitherto obtained have been found unmarketable, because when a higher sulphur content than 75% in the concentrate was sought the loss of sulphur in the tailings was so great as to make the process commercially unworkable at a profit.

According to the present invention the sulphur is made more amenable to separa tion from its gangue by heating the material to cause particles of sulphur to unite, or by sintering or liquating it before effecting a final concentration by froth-flotation procedure; This heating may be preliminary to the final concentraton, or preliminary to the initial or rougher concentration, or may precede both. Some sulphur ores are adapted to yield a sulphur-bearing froth by agitation of the ground sulphur ore in an aqueous pulp, but in the following examples a mineral-frothing agent was used.

Other features and advantages will hereinafter appear in connection with the following examples. 1

Emample 1.Ohio placer ore, from Wyoming was ground to pass ten-mesh, and heat' ed in a retort for thirty minutes at pounds pressure of steam, in the presence of steam and water. The resulting material formed a cake when cool, and was ground for thirty minutes in a pebble mill. The gr'ound material was made into a pulp with water and agitated in, a spitzkasten subaeration frothflotation machine with 0.4 pounds per tonof a ten per cent solution of pine oil in alcohol while froth was separated for seven min utes, yielding a rougher concentrate. This concentrate was re-agitated in the same ma- Application filed April 20, 1928. Serial No. 271,643.

chine for five minutes with added water and with 0.2 pounds per ton of the same solution and separated into a finished froth concentrate and a middling. The results are shown in the following table:

Recover- Assays ies Wt. s. s.

. agitation and that the second agitation was.

continued for six minutes. The results are shown in; the following table:

' Recover- Assays I ies 7., Wt. s. s.

100. 3&4

32.5 98.0. 82.9 4.9 71.5 9.1 Tails '1 .626 5. 8.0

Example 3.-Another lot ,of the Ohio placer ore, ground to pass 10-mesh' was sintered in a retort for minutes at forty pounds steam pressure. Theresulting material was ground in a pebble mill and made 4 into a pulp with water and agitated for ten minutes in the same machine with the addi-' tion of 0.1 pound of pine oil per ton of ore. The resulting concentrates were sintered in the same way, reground and refloated by agitation in a pulp in the same machine with the addition of 0.1 pound per ton of pine oil for seven minutes, to yield a second or finished concentrate, and a middling. The results are shown in the following table:

Assays gg Heads 54. 9 Conn 98. 5 86. 2 Midd 46. 8 10. 6 Tails 4. 5 3. 2

spectively 78.12% and 22.2% sulphur.

This concentrate was melted under a steam pressure of 35 pounds'to the square inch,

roken down to aboutquarter-inch size and washed on a ten-mesh screen. The oversize contained 92% sulphur and was suitable for some uses. For the presentpur ose it was combined with the undersize an ground to pass one-hundred mesh. An aqueous pulp of this ground material was agitated for five minutes with 0.1 pound steam distilled pine oil per ton, to yield a concentrate and a tailing. r This latter concentrate was again agitated, without added agents, for five minhtes, to yield a finished froth concentrate andfla middling. The results are shown in'th e following table:

Aways gg 100. 30. Fin. Cone. 24. 6 96. 7 78. 9 Midd. (F nal). 10. 7 30. 7 10. 5 Mldd. (First) 11.4 22.2 8. 2 is 53.3 1. 4 2. 4

the whole Having thus described certain embodiments of our invention, what we claim is:

1. The process of concentrating sulphurcontaining material which consists in heating the same to cause particles of sulphur to unite, grinding it to size suitable for froth-flotation concentration, agitating an aqueous pulp of the ground material so as to produce a sulphur-bearing froth, and separating the froth.

2. The process of concentrating sulphurcontaining material which consists in heating the samevwith steam to cause particles of sulphur to unite-, grinding the resulting material to a size suitable for froth-flotation concentration, agitating an aqueous pulp of the ground material with a small quantity of a mineral-frothing agent so as to produce a .zulpllliur-bcaring froth, and separating the rot 3. The process'of concentrating sulphur-' containing. material which consists in grinding the material, heating the material to cause particles of sulphur to unite, grinding the resulting material to a size suitable for froth-flotation concentration agitating an aqueous pulp of the ground material so as to produce a sulphur-bearing froth, and separating the froth.

4. The process of concentrating sulphurcontaining material which consists in grinding the material, heating the ground material with steam to cause particles of sulphur to.

unite, grinding the resulting material to a size suitable for froth-flotation concentration, agitating an aqueous pulp of the ground material so as to produce a sulphur-bearing froth, separating the froth, sintering the froth concentrate with steam, grinding the sintered concentrates to a size suitable for froth-flotation concentration, agitating an aqueous pulp of the ground material so as to produce a sulphur-bearing froth, and separating the froth.

In testimony whereof we have aifixed our signatures to this specification.

' EDWARD HOIT NUTTER.

. JOHN W. LITTLEFORD. 

